Chiral Separations of Enantiomeric Pharmaceuticals by Capillary Electrophoresis Using Sulphobutyl Ether ?-Cyclodextrin as Isomer Selector

Abstract

Capillary electrophoresis has developed into an extremely useful technique for the separation of optical isomers. High efficiencies and the availability of many types of isomer selectors allowing rapid and inexpensive methods development make capillary electrophoresis (CE) an attractive alternative to gas chromatography (GC) and high-pressure liquid chromatography (HPLC) for the determination of chiral purity. In this research the separation of the enantiomers of some chiral pharmaceuticals was investigated using anionic sulphobutyl ether-beta-cyclodextrins as isomer selectors. These chiral selectors have a large countercurrent mobility, making them inherently advantageous as selectors as compared to neutral cyclodextrins. The effects of pH, buffer composition and selector concentration on the chiral separation of these compounds was investigated. All of the compounds studied were successfully resolved by the sulphobutyl ether beta-cyclodextrins (SBE-beta-CDs) typically with run times of less than 20 min using low concentrations of the SBE selector (1-5 mM).